You will also see app updates that may have a negative effect on your battery performance. App updates happen in the background by default and users rarely even know that the app was updated, unless they pay attention to the small blue dot next to the app after it has been updated. It is easy to misinterpret a change to an iOS update that requires action on your part to complete and you see the confirmation screen after it has been updated.
Some developers such as Meta have been updating their apps as much as 10 times in just the last month attempting to fix bugs so it is difficult to determine if an issue is due to the app update or iOS update. Check the apps using your Battery at Settings > Battery and scroll down to review the graph showing rate of drop and the top apps noted below the graph that are consuming the battery. Some apps will have background processes that will consume the battery even when you are not using the app. Background App Refresh has no effect on these operations, as that setting is only for a UI refresh.
As Zachyy said, every iOS update will cause your phone to re-index its files and will increase battery usage during that time. We see these same type of posts after every update, then they go away after the indexing stops. It has been that way for every update in the past and you can expect it again on the next iOS update.